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oidc.go
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oidc.go
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package oidc
import (
"bytes"
"encoding/json"
"fmt"
"html/template"
"net"
"net/http"
"net/url"
"os"
"strings"
"time"
gooidc "github.com/coreos/go-oidc"
jwt "github.com/dgrijalva/jwt-go"
log "github.com/sirupsen/logrus"
"golang.org/x/oauth2"
"github.com/argoproj/argo-cd/common"
"github.com/argoproj/argo-cd/util/cache"
"github.com/argoproj/argo-cd/util/dex"
httputil "github.com/argoproj/argo-cd/util/http"
"github.com/argoproj/argo-cd/util/rand"
"github.com/argoproj/argo-cd/util/settings"
)
const (
GrantTypeAuthorizationCode = "authorization_code"
GrantTypeImplicit = "implicit"
ResponseTypeCode = "code"
)
// OIDCConfiguration holds a subset of interested fields from the OIDC configuration spec
type OIDCConfiguration struct {
Issuer string `json:"issuer"`
ScopesSupported []string `json:"scopes_supported"`
ResponseTypesSupported []string `json:"response_types_supported"`
GrantTypesSupported []string `json:"grant_types_supported,omitempty"`
}
type ClientApp struct {
// OAuth2 client ID of this application (e.g. argo-cd)
clientID string
// OAuth2 client secret of this application
clientSecret string
// Callback URL for OAuth2 responses (e.g. https://argocd.example.com/auth/callback)
redirectURI string
// URL of the issuer (e.g. https://argocd.example.com/api/dex)
issuerURL string
// client is the HTTP client which is used to query the IDp
client *http.Client
// secureCookie indicates if the cookie should be set with the Secure flag, meaning it should
// only ever be sent over HTTPS. This value is inferred by the scheme of the redirectURI.
secureCookie bool
// settings holds Argo CD settings
settings *settings.ArgoCDSettings
// provider is the OIDC provider
provider Provider
// cache holds temporary nonce tokens to which hold application state values
// See http://tools.ietf.org/html/rfc6749#section-10.12 for more info.
cache *cache.Cache
}
func GetScopesOrDefault(scopes []string) []string {
if len(scopes) == 0 {
return []string{"openid", "profile", "email", "groups"}
}
return scopes
}
// NewClientApp will register the Argo CD client app (either via Dex or external OIDC) and return an
// object which has HTTP handlers for handling the HTTP responses for login and callback
func NewClientApp(settings *settings.ArgoCDSettings, cache *cache.Cache, dexServerAddr string) (*ClientApp, error) {
a := ClientApp{
clientID: settings.OAuth2ClientID(),
clientSecret: settings.OAuth2ClientSecret(),
redirectURI: settings.RedirectURL(),
issuerURL: settings.IssuerURL(),
cache: cache,
}
log.Infof("Creating client app (%s)", a.clientID)
u, err := url.Parse(settings.URL)
if err != nil {
return nil, fmt.Errorf("parse redirect-uri: %v", err)
}
tlsConfig := settings.TLSConfig()
if tlsConfig != nil {
tlsConfig.InsecureSkipVerify = true
}
a.client = &http.Client{
Transport: &http.Transport{
TLSClientConfig: tlsConfig,
Proxy: http.ProxyFromEnvironment,
Dial: (&net.Dialer{
Timeout: 30 * time.Second,
KeepAlive: 30 * time.Second,
}).Dial,
TLSHandshakeTimeout: 10 * time.Second,
ExpectContinueTimeout: 1 * time.Second,
},
}
if settings.DexConfig != "" && settings.OIDCConfigRAW == "" {
a.client.Transport = dex.NewDexRewriteURLRoundTripper(dexServerAddr, a.client.Transport)
}
if os.Getenv(common.EnvVarSSODebug) == "1" {
a.client.Transport = httputil.DebugTransport{T: a.client.Transport}
}
a.provider = NewOIDCProvider(a.issuerURL, a.client)
// NOTE: if we ever have replicas of Argo CD, this needs to switch to Redis cache
a.secureCookie = bool(u.Scheme == "https")
a.settings = settings
return &a, nil
}
func (a *ClientApp) oauth2Config(scopes []string) (*oauth2.Config, error) {
endpoint, err := a.provider.Endpoint()
if err != nil {
return nil, err
}
return &oauth2.Config{
ClientID: a.clientID,
ClientSecret: a.clientSecret,
Endpoint: *endpoint,
Scopes: scopes,
RedirectURL: a.redirectURI,
}, nil
}
// generateAppState creates an app state nonce
func (a *ClientApp) generateAppState(returnURL string) string {
randStr := rand.RandString(10)
if returnURL == "" {
returnURL = "/"
}
err := a.cache.SetOIDCState(randStr, &cache.OIDCState{ReturnURL: returnURL})
if err != nil {
// This should never happen with the in-memory cache
log.Errorf("Failed to set app state: %v", err)
}
return randStr
}
func (a *ClientApp) verifyAppState(state string) (*cache.OIDCState, error) {
res, err := a.cache.GetOIDCState(state)
if err != nil {
if err == cache.ErrCacheMiss {
return nil, fmt.Errorf("unknown app state %s", state)
} else {
return nil, fmt.Errorf("failed to verify app state %s: %v", state, err)
}
}
_ = a.cache.SetOIDCState(state, nil)
return res, nil
}
// HandleLogin formulates the proper OAuth2 URL (auth code or implicit) and redirects the user to
// the IDp login & consent page
func (a *ClientApp) HandleLogin(w http.ResponseWriter, r *http.Request) {
oidcConf, err := a.provider.ParseConfig()
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
scopes := make([]string, 0)
if config := a.settings.OIDCConfig(); config != nil {
scopes = config.RequestedScopes
}
oauth2Config, err := a.oauth2Config(GetScopesOrDefault(scopes))
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
returnURL := r.FormValue("return_url")
stateNonce := a.generateAppState(returnURL)
grantType := InferGrantType(oauth2Config, oidcConf)
var url string
switch grantType {
case GrantTypeAuthorizationCode:
url = oauth2Config.AuthCodeURL(stateNonce)
case GrantTypeImplicit:
url = ImplicitFlowURL(oauth2Config, stateNonce)
default:
http.Error(w, fmt.Sprintf("Unsupported grant type: %v", grantType), http.StatusInternalServerError)
return
}
log.Infof("Performing %s flow login: %s", grantType, url)
http.Redirect(w, r, url, http.StatusSeeOther)
}
// HandleCallback is the callback handler for an OAuth2 login flow
func (a *ClientApp) HandleCallback(w http.ResponseWriter, r *http.Request) {
oauth2Config, err := a.oauth2Config(nil)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
log.Infof("Callback: %s", r.URL)
if errMsg := r.FormValue("error"); errMsg != "" {
http.Error(w, errMsg+": "+r.FormValue("error_description"), http.StatusBadRequest)
return
}
code := r.FormValue("code")
state := r.FormValue("state")
if code == "" {
// If code was not given, it implies implicit flow
a.handleImplicitFlow(w, r, state)
return
}
appState, err := a.verifyAppState(state)
if err != nil {
http.Error(w, err.Error(), http.StatusBadRequest)
return
}
ctx := gooidc.ClientContext(r.Context(), a.client)
token, err := oauth2Config.Exchange(ctx, code)
if err != nil {
http.Error(w, fmt.Sprintf("failed to get token: %v", err), http.StatusInternalServerError)
return
}
idTokenRAW, ok := token.Extra("id_token").(string)
if !ok {
http.Error(w, "no id_token in token response", http.StatusInternalServerError)
return
}
idToken, err := a.provider.Verify(a.clientID, idTokenRAW)
if err != nil {
http.Error(w, fmt.Sprintf("invalid session token: %v", err), http.StatusInternalServerError)
return
}
flags := []string{"path=/"}
if a.secureCookie {
flags = append(flags, "Secure")
}
cookie, err := httputil.MakeCookieMetadata(common.AuthCookieName, idTokenRAW, flags...)
if err != nil {
http.Error(w, fmt.Sprintf("%v", err), http.StatusInternalServerError)
return
}
w.Header().Set("Set-Cookie", cookie)
var claims jwt.MapClaims
err = idToken.Claims(&claims)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
claimsJSON, _ := json.Marshal(claims)
log.Infof("Web login successful. Claims: %s", claimsJSON)
if os.Getenv(common.EnvVarSSODebug) == "1" {
claimsJSON, _ := json.MarshalIndent(claims, "", " ")
renderToken(w, a.redirectURI, idTokenRAW, token.RefreshToken, claimsJSON)
} else {
http.Redirect(w, r, appState.ReturnURL, http.StatusSeeOther)
}
}
var implicitFlowTmpl = template.Must(template.New("implicit.html").Parse(`<script>
var hash = window.location.hash.substr(1);
var result = hash.split('&').reduce(function (result, item) {
var parts = item.split('=');
result[parts[0]] = parts[1];
return result;
}, {});
var idToken = result['id_token'];
var state = result['state'];
var returnURL = "{{ .ReturnURL }}";
if (state != "" && returnURL == "") {
window.location.href = window.location.href.split("#")[0] + "?state=" + result['state'] + window.location.hash;
} else if (returnURL != "") {
document.cookie = "{{ .CookieName }}=" + idToken + "; path=/";
window.location.href = returnURL;
}
</script>`))
// handleImplicitFlow completes an implicit OAuth2 flow. The id_token and state will be contained
// in the URL fragment. The javascript client first redirects to the callback URL, supplying the
// state nonce for verification, as well as looking up the return URL. Once verified, the client
// stores the id_token from the fragment as a cookie. Finally it performs the final redirect back to
// the return URL.
func (a *ClientApp) handleImplicitFlow(w http.ResponseWriter, r *http.Request, state string) {
type implicitFlowValues struct {
CookieName string
ReturnURL string
}
vals := implicitFlowValues{
CookieName: common.AuthCookieName,
}
if state != "" {
appState, err := a.verifyAppState(state)
if err != nil {
http.Error(w, err.Error(), http.StatusBadRequest)
return
}
vals.ReturnURL = appState.ReturnURL
}
renderTemplate(w, implicitFlowTmpl, vals)
}
// ImplicitFlowURL is an adaptation of oauth2.Config::AuthCodeURL() which returns a URL
// appropriate for an OAuth2 implicit login flow (as opposed to authorization code flow).
func ImplicitFlowURL(c *oauth2.Config, state string, opts ...oauth2.AuthCodeOption) string {
var buf bytes.Buffer
buf.WriteString(c.Endpoint.AuthURL)
v := url.Values{
"response_type": {"id_token"},
"nonce": {rand.RandString(10)},
"client_id": {c.ClientID},
"redirect_uri": condVal(c.RedirectURL),
"scope": condVal(strings.Join(c.Scopes, " ")),
"state": condVal(state),
}
for _, opt := range opts {
switch opt {
case oauth2.AccessTypeOnline:
v.Set("access_type", "online")
case oauth2.AccessTypeOffline:
v.Set("access_type", "offline")
case oauth2.ApprovalForce:
v.Set("approval_prompt", "force")
}
}
if strings.Contains(c.Endpoint.AuthURL, "?") {
buf.WriteByte('&')
} else {
buf.WriteByte('?')
}
buf.WriteString(v.Encode())
return buf.String()
}
func condVal(v string) []string {
if v == "" {
return nil
}
return []string{v}
}
// OfflineAccess returns whether or not 'offline_access' is a supported scope
func OfflineAccess(scopes []string) bool {
if len(scopes) == 0 {
// scopes_supported is a "RECOMMENDED" discovery claim, not a required
// one. If missing, assume that the provider follows the spec and has
// an "offline_access" scope.
return true
}
// See if scopes_supported has the "offline_access" scope.
for _, scope := range scopes {
if scope == gooidc.ScopeOfflineAccess {
return true
}
}
return false
}
// InferGrantType infers the proper grant flow depending on the OAuth2 client config and OIDC configuration.
// Returns either: "authorization_code" or "implicit"
func InferGrantType(oauth2conf *oauth2.Config, oidcConf *OIDCConfiguration) string {
if oauth2conf.ClientSecret != "" {
// If we know the client secret, we are using the 'authorization_code' flow
return GrantTypeAuthorizationCode
}
if len(oidcConf.ResponseTypesSupported) == 1 && oidcConf.ResponseTypesSupported[0] == ResponseTypeCode {
// If we don't have the secret, check the supported response types. If the list is a single
// response type of type 'code', then grant type is 'authorization_code'. This is the Dex
// case, which does not support implicit login flow (https://github.com/dexidp/dex/issues/1254)
return GrantTypeAuthorizationCode
}
// If we don't have the client secret (e.g. SPA app), we can assume to be implicit
return GrantTypeImplicit
}